module volume_increasing_and_decreasing
  depends on increasing_and_decreasing

  sort declarations
    expand :: increase

    contract :: decrease

  axioms
    affected_property(X) = volume if instance(X, expand).

    false if instance(X, expand),
             from_value(X, FV),
             -instance(FV, volume_value).

    false if instance(X, expand),
             -defined_base(X).

    false if instance(X, expand),
             base(X, B),
             -instance(B, tangible_entity).

    impossible occurs(X) if instance(X, expand),
                            from_value(X, FV),
                            base(X, B),
                            -volume(B, FV).


    affected_property(X) = volume if instance(X, contract).

    false if instance(X, contract),
             from_value(X, FV),
             -instance(FV, volume_value).

    false if instance(X, contract),
             -defined_base(X).

    false if instance(X, contract),
             base(X, B),
             -instance(B, tangible_entity).

    impossible occurs(X) if instance(X, contract),
                            from_value(X, FV),
                            base(X, B),
                            -volume(B, FV).